diff --git a/packaging/macos/README.md b/packaging/macos/README.md
index ece4995d55..19fab4d3cc 100644
--- a/packaging/macos/README.md
+++ b/packaging/macos/README.md
@@ -41,8 +41,8 @@ The release runner (`ludovics-mac-mini-release`, label `horizon-release`, `MAC_R
 LaunchAgent whose jobs run in their own security session, where the login keychain is locked.
 So signing uses a keychain of its own, `~/Library/Keychains/horizon-signing.keychain-db`,
 holding only the Developer ID identity, Apple's "Developer ID Certification Authority" and the
-notarytool profile `horizon-notary` (the App Store Connect team key "App Store Connect API -
-GitHub CI (DISPO)"). Its password is the item "Horizon signing keychain" in the Agents vault.
+notarytool profile `horizon-notary` (an App Store Connect API key of Horizon's own Apple team,
+YYJU63HSD4, the team of the Developer ID above; never a key of another team). Its password is the item "Horizon signing keychain" in the Agents vault.
 `keychain.sh unlock` (each job's first macOS step) reads it with the fleet's 1Password service
 account, unlocks the keychain, checks the identity and the profile are there and hands both to
 the later steps; `keychain.sh lock` ends the job. Nothing secret is in the repository or on
@@ -57,8 +57,10 @@ Setting it up again (a new Mac, a renewed certificate):
    that password, imports the identity and its intermediate, removes any other identity, lets
    `codesign` use the key without a prompt and deletes the .p12. (The login keychain also holds
    other people's Apple Development and Distribution identities: never those.)
-3. `packaging/macos/keychain.sh notary`: the notarytool profile, from the App Store Connect key
-   (written to a private temporary file and deleted).
+3. `packaging/macos/keychain.sh notary`: the notarytool profile, from team YYJU63HSD4's App Store
+   Connect API key in the Agents vault (written to a private temporary file and deleted). Name its
+   1Password item with `MACOS_NOTARY_ITEM`: the script's default still points at another team's key,
+   which Horizon must never use.
 4. The repository variable `MACOS_SIGN_IDENTITY`.
 
 The certificate and its intermediate expire on 1 February 2027: renew the certificate in the